Bicycles and bicycle racing have been around for more than 100 years, the art is evolved and generally well known.
The bicycle business has grown a lot in recent years as persons become more health conscious and recognize the many benefits cycling provides such as better cardiovascular health, endurance, and weight loss. Bicycles make it easy to experience the outdoors, and make for great transportation having low environmental impact. It's a low physical impact activity that's also great for older persons. Bike racing is more popular now than ever before at all ages.
The bicycle has become an extremely efficient machine. Manufacturers sell bikes today that are in the 10-15 pound range out of the box. Bicycle and component manufacturers vie for sales touting stiffness and strength, light weight, and aerodynamic features that save mere seconds over distance. These savings are often expressed in time saved over a 40 kilometer course, as watts saved as a measure of expended power or as a reduction in aerodynamic drag. Bike frames used to be steel. But today aluminum, titanium or carbon fiber are more common.
Even bike frames are made aerodynamic. Brakes are minimized and hidden. Rear wheels can be tucked in behind the frame, dimpled like golf balls, have toroidal shapes, employ smoothing fillers between tire and wheel, use bladed spokes or have other features to alter air flow patterns, reduce drag, and go faster. As aero optimization evolves even minimal savings are important. Racers wear tight clothing, shave their legs, and wear shoe covers. Even some shoe cleats are dimpled to save a few watts.
Wind resistance and drag is clearly one of the biggest problems cyclists must overcome. But it is the human body that makes the most drag on a bicycle. Positioning that can narrow or otherwise reduce the body's profile is especially valuable racing, touring or commuting. As the bicycle and handlebar combination is already highly evolved and the field of the art is crowded, small changes are significant.
In racing the difference between winning and losing can be mere fractions of a second. The 1989 Tour de France was won by just 8 seconds after more than 2000 miles. Stage 7 of the 2017 Tour de France was won by just 6 millimeters (mm) after 132 miles. There are 1,609,344 mm in 1 mile. The Tissot timing system clocked the difference between 1st and 2nd place at 0.0003 seconds. What may have been a tie or dead heat years ago might not be today. Better timing and photographic means separate riders and make any aerodynamic benefit or other advantage critically important.
Wind-cheating aero designs are important in bike design for efficiency, handling and marketing. The time trial (TT) handlebar or aerobar centers a rider's hands and arms in a forward position to approach a more arrow-like body position that naturally pierces the wind and minimizes aerodynamic drag. Its rider goes faster for the same power output. But the TT bar is awkward, unsuitable for many conditions, requires a high learning curve and places the hands far from the brakes. This makes it inappropriate in many situations, and it is often banned from road races and group rides.
Another aero handlebar was popularized in the 1980s by Tour de France winner Greg Lemond. Bringing the arms in is a known aerodynamic advantage in cycling. Lemond's Drop-In Bar sold by Scott, a European manufacturer known for ski gear, was essentially a contemporary road bar with extended lower portions that allowed more hand positions. These lower grips extended inward perpendicular to the bicycle frame, protruding inward from the lowest section of the traditional road cycling drop bar. This allowed the hands to grip horizontally, that is, with knuckles up and palms down, but with hands and arms brought in to achieve an aerodynamic benefit. Problems with this design were its extra mass—it weighed almost twice as much as its contemporaries—it placed the hands farther from the brakes and it could interfere with the knees when pedaling standing up out of the saddle.